Along with the rapid development of Internet technology and the popularity of large-screen multi-function mobile phones, a large number of mobile data multimedia services and a variety of high-bandwidth multimedia services appear, such as video conferences, television broadcasting, videos on demand, video advertisements, online education and interactive games. This not only meets increasing service requirements of mobile subscribers, but also brings new service growth points to mobile operators. These mobile data multimedia services require that same data may be received simultaneously by multiple subscribers. Therefore, compared with ordinary data services, these mobile data multimedia services are characterised by larger data volumes, long durations and sensitivity to time delays. In order to utilize mobile network resources effectively, a 3rd Generation Partnership Project (3GPP) proposes an MBMS which is a technique for transmitting data from one data source to multiple targets, and thereby implementing network resource sharing as well as increasing the utilization rate of network resources, especially the utilization rate of air interface resources. Here, the network includes a core network and an access network. The MBMS defined by the 3GPP not only can multicast and broadcast a plain-text low-speed type of messages, but also can multicast and broadcast high-speed multimedia services, providing multiple rich video, audio and multimedia services. This undoubtedly meets a trend of future development of mobile data, and provides better service prospects to development of 3rd Generation (3G) mobile communications.
In a Long Term Evolution-Advanced (LTE-A) system, multicarrier aggregation technology is introduced. The multicarrier aggregation technology refers to that: one geographic location is covered by multiple carriers with different frequencies, wherein these carrier frequencies can be either continuous or discrete; and a network side sends data to one User Equipment (UE) simultaneously using two or more carriers, and the UE receives the data on the two or more carriers. At present, the multicarrier aggregation technology stipulated in a protocol includes that:
each UE supports aggregation of at least two Component Carriers (CCs);
a network side allocates the CCs to the UE, and indicates which CC is a Primary Cell (Pcell) of the UE and which CC/CCs is/are Secondary Cell/Cells (Scell/Scells) of the UE;
a UE in an idle state resides in its own Pcell;
the Pcell is always in an activated state;
the network side can close (namely, deactivate) and open (namely, activate) an Scell of the UE;
the UE does not receive a message in a Physical Downlink Control Channel (PDCCH) in a closed Scell;
the UE does not receive a message in a Physical Downlink Shared Channel (PDSCH) in a closed Scell;
the UE does not measure a Channel Quality Indicator (CQI) of a downlink carrier in a closed Scell;
an initial default state of an Scell is “deactivated”;
the UE receives a Broadcast Control Channel (BCCH) message and a Paging message only in the Pcell; and
the UE does not search a public search area of the PDCCH in an Scell.
It can be seen from the above description that, in existing multicarrier aggregation technology, an MBMS is sent using only one CC, mainly to simplify standardized work load and accelerate a standard progress. However, this will lead to premature blind gathering of UEs in an MBMS-including CC, and to increased duration of impact on uplink random access by the MBMS-including CC, thus causing degradation of system performance. For example, assume that there are three CCs, denoted as a CC 1, a CC 2 and a CC 3 respectively, in a multicarrier aggregation system, and an MBMS is provided only in the CC 1. A problem caused by sending the MBMS only in one CC in the multicarrier aggregation system is analyzed below.
A UE accesses the multicarrier aggregation system by randomly selecting a certain CC. Therefore, in theory, the chance of access of the UE by each CC is equal and there are a mean number of UEs accessing by each CC. A network side may learn information on a UE in a Radio Resource Control (RRC) connection state in real time. For example, the network side may learn the CC in which the UE is located. Therefore, the network side can schedule a UE in the RRC connection state to operate in a certain CC as needed, so as to balance the load in each CC. However, as the network side is not able to learn the CC in which a UE in an idle state is located, the network side cannot schedule such a UE into a certain CC. In other words, the UE may not learn in time whether an MBMS currently being transmitted in the MBMS-including CC is an MBMS the UE is interested in. And when the UE receives a notification and gathers to the MBMS-including CC, the UE finds that the MBMS currently being transmitted in the MBMS-including CC is not an MBMS the UE is interested in, leading to the phenomenon of premature gathering of UEs in the MBMS-including CC, which potentially increases duration of impact on uplink random access by the MBMS-including CC. Namely, a probability of a conflict in uplink random access is increased. In addition, in related art, a UE operating or residing in the CC 2 or the CC 3 is not able to learn accurately and timely that the MBMS the UE is interested in has begun to be sent in the CC 1, so that the UE cannot operate or reside in the CC 1 in time to begin to receive the MBMS the UE is interested in.